More than meets the eye, El Charco del Ingenio, Part 2
By Honey Sharp
Impressed for years by El Charco’s native cacti, stately agaves and delicate, colorful succulents, one of the features that intrigued me more recently was a small, terraced gray water filtering water garden set near the Conservatory. Looking more like an attractive educational tool, I have come to know it is an essential source for irrigating the cultivated plants, many on the endangered plant list.
Called an “humedal,” or wetland, in this case, it is man-made. With small terraces and gravity, water can slowly cascade (more like trickle) through wetland plants and stones; it filters and purifies the water originating from the Charco’s Presa de la Obraje, a large dam below the gardens, playing an important role in the Charco’s policy of proper water management.
For this 67-hectares botanical garden, inaugurated in 1982, preserving and restoring the land and sensitive ecology became a top priority. No wonder. Due to decades of over-grazing by sheep and cattle, the soil had been seriously compacted, eroded, and depleted. During the rainy season, unstable land causing mudslides occurred; during the dry season, it was a desert: flora and fauna biodiversity was lacking.
With major improvements such as terracing and retaining stone walls (as seen along paths) and proper management, the native flora began to spontaneously return. From 130 flora species in 1981, over 600 today are thriving in the wild today. Hundreds more are also propagated in nurseries.
Before awareness of the growing crisis surrounding insufficient local water, this involved creative ways to reconstitute what is essential to the environment.
As Mario Hernández, its director, pointed out recently: “Today when it rains, El Charco acts like a giant sponge capturing water into the ground and the plants roots; it no longer is running off or evaporating. In addition, trees such as mesquite also provide shade to the soil thereby preventing evaporation.”
While strolling—or jogging around its presa and seeing its natural spring, called El Manantial, may appear to show that water is plentiful— depending of course on the season and level of rainfall—at a record-breaking low in 2011, this is not the case. However, such sources paired with creative solutions, such as harvesting rainwater, fortunately have contributed to ways to use water sustainably.
What does this include? As I learned from Mario Hernández, El Charco has three principal approaches:
The pumping of a limited amount of water from the presa to a large tank situated on higher ground, “feeding” it to three cisterns and then circulating it to the propagation plant nurseries.
The filtering of gray water in the “humedal” for irrigation purposes.
The installing of water catchment systems on each building from the entry area and store to the offices, providing year-round water. “But,” as Mario explains, “it is still not enough since it only produces 50,000 liters. That may sound like a lot but it’s amazing how much we all use. We’re simply not aware of it. Many believe that when it’s raining, there’s no problem. Unfortunately in the city it just flows onto the street and doesn’t replenish the water aquifers.”
In conclusion, central to the Garden’s mission as well as OCAS (Observatorio Ciudadano del Agua y Saneamiento), a non-profit organization founded by the ONU and now in SMA, Mexico, is the vital issue regarding how to deal with the region’s dire and quickly diminishing water resources. In a campaign to educate the public while offering practical solutions, models such as El Charco’s is an inspiration to all.